Burner



J. A. DIENNER.

BURNER.

APPLICATION FILED 050.10, 1917. RENEWED JUNE 21,1922. 1,424,808,

SHEET I.

$711113 J" John 0. Dim

Patented Aug. 8, 1922.

3 SHEE T5- h m M m gig??? E J. A. DIENNER.

BURNER. APPLICATION FILED DEC. I0, I91?- HENEWED JUNE 2111922.

Patented Aug. 8, 1922.

3 Sj'lEETSSHEET 2.

- m de; John G. Diem 0w" J A. DIENNER.

BURNER.

APPLICATION FILED DEC. 10, .917.

RENEWED JUNE 21 Sm Jblm C2. Dianne/r (lfto 'ne/gs mm MM narrate star-sis rarest patties.

JOHN A. DIENNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO CHARLES A. BROWN, HARVEY L. HANSON. AND JOHN A. DIENNER, COYARTNERS DOING BUSINESS AS BROWN, HANSON 8r, BOETTCHER, OF CHICAGO, ILLINOIS.

Application filed December 10, 1917, SeriaI'No. 206,431. Renewed June 21, 1922. Serial No. 569,883.

useful Improvement in Burners, of which the following is a. full, clear, concise, and

'rarily enriching the mixture in the combus- 'atomizing burner cannot do.

exact description, reference being had to the accompanying drawings, forming apart of this specification. v i

My invention relates to burners for liquid fuel.

The chief object of the invention'isrto provide a combination of vaporizing and atomizing burners,'in a novel and useful relation.

The vaporizing burner is superior in efiiciency to the atomizing burner.

It requires less combustion space, gives a clean flame, and complete combustion, all of which the The difficulty, primarily, with the vaporizing burner is the requirement for preliminary heating to secure vaporizing of thefuel.

The atomizin'g burner, on the contrary, can be started instantly as it needs no preliminary heating. But, for a given heat output, it requires a decidedly greater combustion space in order to get a clean fire.

I propose to employ an atomizing burner and a vaporizing burner, using the same combustion space,'employing the atomizing burner as a pilot for the main vaporizing burner. The pilot burner, being of small size, uses the combustion space of the larger main burner to secure good combustion.

I also provide means for alternately throwing the burners into and out of action.-

I donot intend to be limited to. alternateaction as I have found that the combustion space may be made to accommodate both burners, the pilot burner being on continuously. This is optional. although I secure better results by alternate action.

Further means is provided for tempotion space where alternate operation is em ployed by providing an overlap between operations. That is to say. when the main burner is to be started, the pilot burner continues for a short time after the main burner is turned on.

The fuel mixture that is thus thrown into the combustion space is considerably richer because, instead of air only entering throughthe main burner as is the case when the pilot burner only is operating, air and fuel are supplied. Means is also provided for securing a certain overlapping of the functions so that one burner maybe ignited from the other without giving an opportunity for the failure of ignition. The atomizing burner may be provided with automatic spark plug ignition to insure lighting of the same, but I have shown it as applied to manual control for starting only as it is unnecessary after one of the burners is ignited. I

My improved burner apparatus has particular application to steam boilers and provides automatic regulating means for the burner which operates to shut down the same when certain conditions arise within the boiler, such as excessive steam pressure or the lowering of the water level below that conductive to safe and efiicient operation of the boiler.

The main vaporizing burner has only one.

Patented Aug. 8, 1922.

practical rate of Working which is approximately its maximum rate. Any appreciable reduction in the rate of supplying vaporized fuel thereto, results in an irregular surging action and an uneven distribution of flame over the burner screen, and if the burner is throttled very low the efiiux of the combustiblevapor from the, perforations in the burner screen soon drops below that of flame propagation and the flame will pass into and be sustained in the burner casting.

Because of the inability of the vaporizing burner to work successfully at any other rate than its approximate maximum rate I operate the burner at this rate until conditions within the boiler necessitate a diminution of heat supply whereupon the burner is completely extinguished.

I have also provided an improvedvpilot burner which operates in alternation with the main burner to retain the vaporizing coil or chamber thereof at a vaporizing temperature during the non-operating intervals of the main burner so that when conditions within the boiler require .it the main burner will be in condition to resume operation immediately, This alternatingoperaintend to be limited to the tion of the main and pilot burners is controlled automatically, and is arranged with a short overlap between the starting of one burner and the extinguishing of the other so that the burners will alternately ignite one another. In addition to keeping the vaporizing coil hot the pilot burner supplies considerable heat to the boiler, enough to prevent chilling of the boiler when the main burner is extinguished. My improved pilot burner is distinctive from pilot burners heretofore used in similar adaptations, in that it atomizes rather v than vaporizes the liquid fuel before mixing it with air. This principle of carburetion doesnot necessitate the application 'of .heat nor .a protracted vaporization, and

' electric motor for running the pilot burner,

showing the control relays therefor, and the automatic operating mechanism for the main fuel valve Figure 3 isa plan view of the same; and

Figure 4 is a vertical sectional view through the atomizingand car-bursting device of the pilot burner.

Referring to the diagrammatic layout in Figure l, the main burner designated 1, comprises a hollow burner casting 2," the up per surface of which is formed with a plurality of ri es 3 which form a combustion screen. The crests of the ridges 3 are slotted to permit the discharge of oil vapor from the interior of the hollow casting 2 up into the combustion space above the casting. The shell 5, surrounding the burner casting 2 extends up into engagement with the boiler above the burner 1 and confines the burning gases under the boiler. The oil vapor is supplied to the hollow burner casting 2 from nozzles 6, discharging into mixing tubes 7- which extend into the interior of the' casting. A gaseous fuel is discharged under pressure from the nozzles 6, and the high velocity of this discharge draws air into the mixing tubes 77 which combines with the gases from the nozzles 6 in the production of a highly combustible mixture. The nozzles 6 are connected by the manifold 8 with the tube 9, passing over the burner casting 2, to the vaporizing coil the combustion from the main vaporizing burner 1 during the operation thereof. Oil

is fed under pressure through the pipe 12 to the vaporizing coil 10, where it is sub jected to the intense heat from the main burner 1 and is vaporized, prior to its dischargefrom the nozzles 6.

In the regulation of the main vaporizing burner 1,I interpose a suitable valve in the oil line'12 which is acted upon by automatic devices, which make the position of the valve subject to conditions within the boiler. For example, if -an excessive steam pressure develops in the boiler or the water level therein falls too low, these automatic devices will operate to close the valve in the fuel line 12 and thereby shut ofi the main burner 1. When these conditions are corrected the valve is opened and the main burner resumes operation. WVhen this main fuel valve closes the main burner 1 is entirely extinguished, an atomizing pilot burner 14 maintaining the vaporizing coil 10 hot until the steam pressure within the boiler lowers, or the water level therein is raised,whereupon the main fuel valve automatically reopens and the main burner 1 resumes operation. The pilot burner 14 is adapted to operate alternately with the main burner 1 to keep the vaporizing coil 10 at l a vaporizing temperature, and the two burners are arra'ngedto operate in over lapping alternation so that one will ignite the other as they alternately go on and go off.

This atomizing pilot burner, see Figure 4, comprises a stationary housing or mixing barrel -15 and a rotor element 16 mounted therein and driven by the electric motor '17. The horizontal tubular member 16 of the rotor 16 is journaled in the bearing 15- of member 16 into the mixing barrel 15 by centrifugal force, and imparting an additional impulse to the air over that of the fan blades 19. Some of the tubes 22 are provided with transverse openings intermediate their length, which discharge a small amount of air into the midzone of the mixing space. Radially projecting pins 23 are mounted in rows around the inner circumference of the mixing barrel 15, between the tubes 22.

The combined action of the centrifugal mixing tubes 22 and the stationary pins 23 is to a plurality of blades 25 lying radially to the.

flange, this spreading or spraying disc being positioned in front of the fuel jet 26,

which opens into the bottom of the barrel 15. The upper end of the jet 26 is directed towards the spraying disc in such a manner that the fuel discharge from the nozzle will strike the spreading disc and will then be spread or sprayed into the space between the barrel 15 and the rotating tubular member 16. A flange 27 on the front end of the tubular member 16 confines the discharge of mixture from the barrel 15 to that volume of the mixture moving-in the outer zone of the mixing space where it is under the action of the air issuing from the tubes 22. For particular details of this atomizing carbureter or mixing device, attention is directed to the application of William H. Winslow,

Serial No. 147,990 filed February 12, 1917 for an improvement in carburetion.

From the mixing barrel 15, the mixture passes into the discharge horn 29 which is curved to direct the efilux of the mixture towards the apex of the conical vaporizing coil 10, as shown in Figure 1.

' As shown in Figure 4, a hot air connection 30 may be provided leading from adjacent the boiler, or the main burner 1, to supplly heated air to the flared extension 18.

suitable valve 31 is interposed in the fuel pipe 32 leading to the discharge jet 26, and this valve is adapted to be controlled by the action of the centrifugal governor-33,mounted on the shaft 20. Rotation of the shaft 20 results in outward movement of the fly-ball governor 33 and concurrent opening of the .valve '31, a spring 34 returning the governor to normal position and closing the valve 31, when the shaft 20 ceases rotating. The operation of the pilot burner will be apparent from'the foregoing description, the proportion of the parts being such that the discharge of combustible mixture from the horn t 29 is at a higher velocity than that of flame propagation so that combustion occurs more within the/helical vaporizing coil 10 than within the horn 29.

I have showna spark plug 85, spark coil 86 and push switch 87 for igniting the pilot burner upon starting of the system.

Referring now to the circuits illustrated in Figure 1, the main regulating circuit for regulating the operation of the main burner 1 is indicated in heavy lines. A storage battery, or similar source of current 36 is connected by one terminal with one pole of a breaker 38 is immaterial to the present invention, it may comprise a spring pressed diaphragm having one side thereof subjected to the steam pressure from the boiler as illustrated, or any other suitable arrangement. Connected in series with the pressure operated circuit breaker 38 by 'way of the wire 42 is the low'water circuit breaker 43. The circuit breaker shown is controlled thermally, but like the circuit breaker 38, the particular principle of operation of this element is immaterial to the present invention. ,A member 45 projects laterally from the header 46, or boiler shell in low pressure boilers, at approximately the-lowest water level desirable. Heat dissipating. flanges 47 dissipate the heat imparted to the member 45 by the water therein, and maintain the member 45 at a certain linear expansion, with the contacts 48-49 engaged and the circuit complete.

When the water level drops below the expansible member 45, steam enters this member, and the rate of heat transfer thereto is greater. The flanges 47 have a con stant heat radiating capacity and consequently, the member 45 expands slightly along its linear dimension, separating the contacts 48-49 and interruptlng the circuit. -A wire 50 connects the contact 49 with one end of the Winding of the regulating relay 51. A wire 52 connects the other pole of the storage battery 36 with the other end of the winding v51.

The shut off circuit for the pilot burner comprises the wire 54, connected above the switch 37, the thermostatic circuit breaker 55, the wire 56 and the relay' 57. The thermostatic circuit breaker 55 is positioned in, or adjacent, the main burner '1, where the differential expansion members 58 will be subjected to the heat from the main burner but will be entirely out of the influence of the pilot burner; The arrangement is such that when the thermostatic contact members 58 are cold contact will be had between these members and the contact strip 59, the circuit then being complete from the stora e battery 36 through switch 37, wire 54, t ermostatic circuitbreaker 55' wire 56, relay winding 57 and wire 52,- back to battery 36.

When the main burner 1 has been ignited and has burned for a short interval, the dif-- ferential expansions occurring between the members 58 will flex the same to one side, thus breaking its contact with the strip 59, interrupting the circuit and de-energizing the relay 57 for a purpose to be hereinafter described. 1

The motor circuit is-cut in on the battery 36, short of the switch 37 and is not directly subject to the position thereof. This circuit comprises the wire 61, contacts 62, wire 63, motor 17, wire 64, the contacts of the relays 5157 and the wire 65 extending back to the other terminal of the battery 36. The wire 64 connects with the armature 66 of the regulating relay 51 and with the front contact of the shut off relay 57. The wire 65 connects with the armature 68 of the shut-off relay 57 and with the back contact 69 of the regulating relay 51. When the double pole, single throw switch 37 is closed, one blade thereof shunts the contact 62 by way of wires 7172, for a purpose to be hereinafter described.

The functions of the relays 5157 and the mode ofl securing the alternate operation of the main and pilot burners will be apparent from inspection of Figures 2 and 3. The motor 17 for driving the mixing device of the pilot burner, is mounted on a suitable base portion 7 3, upon which is also mounted the pedestal bearing 74, the main fuel I valve 75 in the main fuel litre 12, previously referred to. The motor shaft 20 is provided with a worm screw 76, cut the-rein which meshes with and slowly rotates the worm wheel 77, in the direction indicated by the arrow. This worm wheel has a shaft 77 journaled in the pedestal bearing 74, as better shown in Figure 3, upon the end of which is rigidly secured a one-tooth gear 78. This one-tooth gear is adapted to mesh in the internal rack bar 79 which is mounted for vertical reciprocation in the guiding plate 80.

The worm wheel shaft 7 7 p'asses through a longitudinal slot-81 in'the. plate 80, and guiding screws 82 threading"into' the plate 80, embrace and guide the rack bar 79. The right-hand end of the plate 80 is formed with a reduced cylindrical portion 83, which constitutes a solenoid plunger extending into the center of the relay magnet 51. A compression spring 8 confined between the relay 51 and the guiding plate 80 normally tends to retain the plate 80 and rack bar 79 in the positions shown. Thus, the relay 5l.has .the two-fold function of a relay for opening the motor circuits by separating the contacts 59 and 60 when energized and of a so lenoid for, shifting the position of the rack bar 79 relative to the one-tooth gear 78.

The right-hand rack teeth 86 are adapted to be engaged by the one-tooth gear 78 when the relay 51 is deenergized, and moved down in the direction of the arrow to the position shown, further movement being imof the arrow will slowly raise the rack bar 79 up as indicated by the arrow until the gear 78 encounters the toothless portion 87 coextensive with the rack teeth 87. Here the gear 7 8 will rotate idly as long as the motor 17 runs, until the relay 51 is de-energized whereupon the rack bar 79 will be shifted by the spring 84, casting the right-hand rack teeth 86 into engagement with the one-tooth gear 78 and moving the rack bar 79 slowly down to the position illustrated. The space between the pairs of opposing teeth 86 and .87 is made sufficiently wide so that when the single tooth on the gear 78 is engaging in one set of teeth, it will just clear the tips of the teeth of the other set.

A valve operating arm 89 extends from themain fuel valve and has pivotalconnection with the rack bar 79 at 90. This arm 89 assists in guiding the rack bar 79. The valve element within the main fuel valve 75 is arranged so that in the descended position of the rack bar 79, the valve will be completely closed, and in the raised position of the rack bar 79 the Valve will be completel opened. A shelf portion 91, integral with the pedestal bearing 74, supports the relays 5157, side .by side, as shown in Figure 3. The 'two contact springs 62 are mounted on the base 73 and have ablock of insulation 92 secured to the lower spring which is adapted to be engaged by the end of the rack bar 79 when in its descended position, this engagement separating the two contacts.

These contacts are inserted in the motor circuit as shown in Figure 1, to insure that the main fuel valve 75 will be closed when the burner is completely shut off, as at the end of a days run.

The operation of the invention will now be described: The only operation incumbent upon the operator, or attendant, in starting the burner, is the closing of the switch 37.

This completes the regulating circuit through the pressure operated circuit breaker 38, the low water circuit breaker 43', the relay winding 51, and the storage battery 36,

back to the switch 37. This also completes the shut off circuit for the electric motor,

from the switch 37 to wire 54, therrno-staticv circuit breaker 55', which is closed when cold, wire 56, relay winding 57, wire 52, storage battery 36 and back to the switch 37.

In addition, the closure of the switch 37 puts one blade thereof in short circuit with the contacts 62, by way of the wires 71 and 72. The action of the circuits will now be described.

plunger 83, shifting the rack bar 79 so that the left-hand teeth 87 thereof will be engaged by the one-tooth gear 78. Energization of the Winding of the relay 57 draws the armature 68 into engagement with the front contact 67, closing the motor circuit from the battery 36 to wire 65, armature 68, front contact 67, wire 64, motor 17, wire 63, contacts 62 (if they happen to be closed), or wire 72, switch 37, wire 71, wire 61 and back to battery 36, The rotation of the motor 17 now operates throughthe centrifugal gover-v nor 33 to open the pilot fuel valve 31, thoroughly carburet the liquid fuel issuing from the jet 26, and discharge the resulting mixture from the horn 29 into the centre of the vaporizing coil 10.

This mixture is then ignited by a match inserted through a sight hole adjacent the horn 29. The combusting gases permeate the coil 10, heating the same to a vaporizing temperature and aiding materially in heat ing the cold water in theboiler. Simultaneous with this action, the one-tooth gear 7 8 is slowly-elevating the rack bar 79 to the position corresponding to the open position of the main fuel valve 75. The complete opening of thisvalve should be deferred until the vaporizing coil 10 has reached an approximate vaporizing temperature, other wise the initial discharge from the nozzles 6 will be liquid rather than gaseous. The rapidity of opening of the main fuel valve 75 is determinable by the pitch angle of the' Worm screw 76 and worn Wheel 77 ,.which govern the rate of rotation of the one-tooth gear 78. The one-tooth gear 78 soon reaches the toothless portion 87 of the rack bar 79 corresponding to full open position of the valve 75, and idly rotates there as long as the motor 17 runs, the single tooth on the gear 78 engaging the toothless portion 87" and oscillating slightly the rack bar 79 every revolution against the magnetic attraction of the solenoid plunger 83. The combustible gases issuing fromthe slotted ridges 3 of the main burner 2 are ignited by the flame from the pilot burner 14 and commence heating the boiler. The heat from the main burner 1 soon bows the differential expansion 4 members 58 of the thermo-static circuit breaker 55 to the position shown in the dotted lines interrupting the short circuit and tie-energizing the relay 57. This releases the armature 68 from the front contact 67 of this and the solenoid plunger 83 in attracted position. Upon cessation of the operation of the motor 17, the centrifugalgovernor 33 oper rates to close the pilot fuel valve 31, and accordingly the pilot burner 14 is entirely extinguished.

With the main burner 1 now burning steadily, assume that an excessive steam pressure is generated in the boiler or the water level in the boiler falls below a safe level. This will-act upon either of the circuit breakers 38 or 43 and interrupt the regulat ing circuit and de-energize the regulating relay 51. The de-energization of thisrelay allows the armature 66 to move back into engagement with theback contact 69, closing the motor circuit, and releases the solenoid plunger 83, the compression spring 84, shifting the plate and rack bar 7 9, so that the right-hand teeth 86 thereof. come into engagement with the one-tooth gear 78] As stated,.the motor circuit has been completed and the motor proceeds to initiate the operation of the pilot burner 14 by opening centrifugally the pilot fuel valve 31, the combustible mixture'issuing from the horn 29 soon being ignited by the still burning main burner 1. (Joncurrently, the slow rotation .of the one-tooth gear 78 is slowly descending the rack bar 79 to its lowermost position, closing the main fuel valve 75. The gear 78 now idly rotates against the toothless portion 86' slightly shifting the rack bar 79 each revolution against the compression of the spring 84. The main burner '1 is now shut off, and the pilot burner ignited and in full operation to keep the vaporizing coil 10 at a vaporizing temperature. Meanwhile, the thermo-static circuit breaker 55 is cooling and contracting to a closed circuit position. The pilot burner 14 will continue operating and the main burner 1 will remain in a shut off condition, until the undesirable conditions within the boiler are corrected. The raising of the water level in the boiler or the gradual lowering of the steam pressure therein will eventually complete the regulating circuit through the circuit breakers 38-43. This completion of the regulating circuit will energize the relay 51, separating the armature 66 and back contact 69.

This does not break the motor circuit, however, inasmuch as the thermo-static circuit breaker 55 has cooled and closed in the interim between the shutting off of the main burner 1 and the present energization of the relay 51. Consequently, the relay 57 is in" an energized condition, its armature 68 and front contact 67 being engaged [and the motor circuit being complete therethrough. The

completion, of the regulating circuit and the energization of the combined solenoid and relay 51' shifts the rack bar 79, so that the onetooth gear 78 will engage inthe left-hand rack teeth 87 and slowly open the fuel valve 7 5. The oil Which then'flows into the vaporizing coil 10 will be quickly vaporized, due to the maintenance of the vaporizing coil 10 at a vaporizing temperature, and will soon generate a combustible mixture in the main burner 1 to be ignited by the flame from the pilot burner.

Ensuing steps in the cycle of operation will be a repetition of those just described, and'this cycle will be gone through again and again, as long as the switch 37 is closed.

In the performance of the cycle, the rack bar 79 will move down to close the main'fuel valve 75 and will engage the block of insulation 92, separating the contacts 62. No effect will be had on the motor circuit, however, as these contacts 62 are short circuited by the switch 37. When steam is no longer required from the boilerand it is desired that the burner be entirely shut off, the switch 37 is opened. This breaks the regulating circuit through the winding of the relay 51 and the shutoff circuit through the winding of the Zflne'lay 57, and removes the short circuit from across the contacts 62.

Consequently, the armature 66 of the relay 51 moves back into engagement with its back contact 69, and completes the circuit for the motor 17, which is not subject to the position of the switch 37. If the rack bar 79 is in its descended position, the contacts 62 will be' separated and the motor will notrun, but if the bar is in a raised position the contacts 62 will be closed and the motor will run, lowering the bar by engagement of the one-tooth gear 78 with the right-hand rack teeth 86 until the rack barengages and separates the contacts 62.

This is to insure that the main fuel valve 75 will be in a closed position when the entire system is shut oifl If desired, a switch 94:

may be connected across the two wires 7 17 2,

which will be operable independently of the main switch 37 to short circuit the contacts 62 when the main switch is in the released and burners in overlapping alternating sequence.

2. In combination, a boiler, a vaporizing burner for heating said boiler, a vaporizing coil for said vaporizing burner, automatic regulating means controlled by conditions within said boiler for stopping and starting said vaporizing burner, an atomizing burner means controlled by said automatic regulating means governing said burners to 1 ,424,s'os

automatically substitute one burner forthe other to heat said vaporizing coil.

3. In combination, an object to be heated,

a vaporizing'burn'er adapted to supply a relatively large quantity of heat to said object, an atomizing burner adapted to supply a relatively small. quantity of heat to said object, heat controlled means governing said burners to limit the maximum temperature of said object, said burners being adapted to heat said object continuously in predetermined sequence.

4. In combination, a boiler, a vaporizing main burner for heating said boiler, a

va orizin coil for said va orizin burner 0' P g a said valve means, and an atomizing pilot 55 burner also controlled by said regulating means to operate in alternation with said vaporizing main burner to keep said vaporizing coil at a vaporizing temperature.

5. In combination, a boiler, a vaporizing main burner, for heating said boiler, a vaporizing coil for said vaporizing burner, valve means-for controlling the flow of liquid fuel to said vaporizing coil, automatic regulating means controlled by conditions within said boiler for'governing the position of said valve means, an atomizing pilot burner adapted to heat said vaporizing coil, said automatic regulating means comprising an electric motor for operating said atomizing pilot burner, and means for automatlcally closing the circuit of said electric motor when said valve means moves to a closed position and for opening the circuit to an open 05 when saidvalve means moves position.

6. In combination, a boiler,a vaporizing main burner for heating said boiler,-a vaporizing coil for said vaporizing burner, an

automizing pilot burner adapted to heat said vaporizing coil, an electric motor for operating saidatornizing pilot burner, valve meansfor controlling. the new of liquid fuel to said vaporizing coil, an automatic regulating means controlled by conditions within said boiler for governing the operating of said motor and the position of said valve means.

7. In combination, a boiler, a vaporizing main burner for heating said boiler, a Va- 1 porizing coil for said vaporizing burner, an

atomizing pilot burner adapted to heatsaid vaporizing coil, an electric motor for operating said atomizlng pilot burner, valve means for controlling the flow of liquid fuel to said vaporizing coil, automatic regulating means controlled by conditions within said boiler for initiating the operation of said motor and for governing the posi tion of said valve means and means operated aaaasos thermally by said vaporizing main burner for stopping the operation of said electric motor.

8. In combination, a vaporizing burner, a vaporizing coil for said vaporizing burner and an etomizing pilot burner operating .alternately with said vaporizing burner for heating said vaporizing coil and automatic regulating means governing the operation of both of said burners.

9. In combination, a boiler having a com bustion chamber, a vaporizing burner arranged to project flames into said chamber, an atomizing burner of smaller capacity than said vaporizing burner adapted to project flames intosaid chamber, said chamber and atomizing burner being proportioned to providev proper combustion space to secure clean burning of the fuel supplied by the atomizing burner, said vaporizing burner having an oil vaporizing coil adapted to be heated by flames from either burner for first vaporizing the oil before burning in said vaporizing burner.

10. In combination, a combustion chamher, a first burner arranged to project flames into said combustion chamber, a second burner arranged to project flames into said combustion chamber, said burners being adapted to operate in predetermined order, and automatic thermally operated means controlled by the temperature in said combustion .chamber for automatically interruptin the operation of said second burner.

, 11. tion chamber, a main vaporizing burner arranged to project flames into said chamber. an atomizing burner of smaller capacity adapted toproject flames into said chamber,

a vaporizer in said combustion chamber subject to the flames from either burner and means controlled jointly by the condi tion of the boiler and by the condition 'of the main burner, governing the atomizing burner.

12. In combination, a boiler having a fire box, a vaporizing burner havinga vaporizing coil in said fire box, an atomlzlng burner for projecting its flame into said fire box 11 combination, a boiler, a combus stantially closed fire box, a burner platehaving a plurality of openings lying in the lower portion. of said fire box, a vaorizer coil above said plate, said coil havmg a nozzle for discharging vaporized fuel below said plate, means for supplying fuel to said vaporizing coil, means external to -the fire box for producing a spray of fuel mixed with air in proper proportions to support combustion, said mixture being directed upon sail coil in the fire box, and automatic means for initiating the discharge of said mixture at predetermined eriods.

15. In combination, a boiler having a substantially closed fire box, a burner plate having a plurality of openings lying in the lower portion of said fire box, a vaporizer coil above said plate, said coil having a nozzle for discharging vaporized fuel below said plate, means for-supplying fuel "to said vaporiz ng coil, means external to the fire box for producing a spray of fuel mixed with air in proper proportions to sup port combustion, said mixture being directed upon said coil in the fire box, said spray producing means being independent of the means for supplying fuel to said coil, and automatic means for operating said spray -producing means in alternating. sequence with the discharge of vaporized fuel below said burner plates.

In witness whereof I hereunto subscribe my name this 17th day of November, A. 1).,

JOHN A. DIENNER. 

